Transit concrete mixer and method of mixing concrete components

ABSTRACT

A transit concrete mixer and method of mixing concrete components, wherein a rotatable drum is provided with a series of inclined blades on its interior, the blades being disposed to move concrete components delivered to the interior of the drum toward the center of the drum when the drum is rotated in one direction and to move them toward an end of the drum when the drum is rotated in the opposite direction. The concrete components may be delivered to the drum through either one or both ends thereof, and the mixed concrete components may be discharged from an end of the drum when the latter is rotated in the opposite direction.

United States Patent 1 1 1111 3,715,107

Paris 1 51 Feb. 6, 1973 [541 TRANSIT CONCRETE MIXER AND 3558,108 1/1971 Jackson ..2s9 177 R METHOD OF MIXING CONCRETE 3,617,031 11/1971 Paris ..259/165 COMPONENTS [76] Inventor: Hugh P. Paris, 3101 Middlefield jg Jenkms Road, Palo Alto, Calif. 94306 6 221 Filed: March 9, 1972 57 ABSTRACT [21] Appi- No.1 23 A transit concrete mixer and method of mixing concrete components, wherein a rotatable drum is 521 US. Cl. ..2s9/14s, 259/3, 259/176 Provided with a Series of inclined blades on its interi- 51 1m. 01 ..B28c 5/18 or, the blades being disposed to move Concrete 531 ld f S h 259 14 148 149 153 1 ponents delivered to the interior of the drum toward 259/162, 164, 165, 169, 170, 171, 175, [76 the center of the drum when the drum is rotated in 177, 3, 14, 30, 81, 89 one direction and to move them toward an end of the drum when the drum is rotated in the opposite [56] References Cited direction. The concrete components may be delivered to the drum through either one or both ends thereof,

UNITED STATES PATENTS and the mixed concrete components may be 1,809,629 6/1931 Koehring ..259/176 discharged from an end of the drum when the latter is 1,825,614 9/1931 Eggert 1,888,100 11/1932 Wilms ..259/l75 3,016,232 1/1962 Domenighetti ..259/177 R 10 Claims, 10 Drawing Figures ....259/176 rotated in the opposite direction.

PATENTED FEB 6 I975 SHEET 10F 3 PATENTEUFEB' 6197-5 SHEET 3 [1F 3 m- UHH .5 1 I I l m. U HMH TRANSIT CONCRETE MIXER AND METHOD OF MIXING CONCRETE COMPONENTS SUMMARY disposed to move concrete components toward the center of the drum when the latter is rotated in one direction, this being really the point of slump test as a low slump concrete is stiff concrete having a very low water content and a rich cement paste when properly mixed. It must be workable with little water as possible and properly mixed in a fine product.

The concrete components may be delivered to the interior of the rotating drum through one or both ends of the drum, and the mixed concrete components may be discharged through an end of the drum when the latter is rotated in the opposite direction.

Other objects and advantages will appear as the specification continues, and the novel features of the invention will be particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference should be made to the accompanying drawings forming part of this specification, in which:

FIG. 1 is a side elevational view of my improved transit concrete mixer showing the latter in a position to receive concrete components from an overhead batchor plant;

FIG. 2 is a development view of the cylindrical body shell of the rotatable drum with appropriate legends being added;

FIGS. 3, 4 and 5 are sectional views taken along the lines 3-3, 44 and 55, respectively, of FIG. 2;

FIGS. 6 and 8 are diagrammatic views showing the drum being loaded with concrete components from both ends and one end only, respectively,;

FIG. 7 is an end elevational view of gates that are used for closing the front and rear ends of the drum;

FIG. 9 is a side elevational view, partly in section, of the rotatable drum showing a detachable rear truncated cone removably secured to the cylindrical body shell, this cone having a central opening of a predetermined size through which the mixed concrete components may be discharged; and

FIG. 10 is a view similar to FIG. 9, but showing a central outlet opening of a larger size, whereby faster discharge of the mixed concrete components may be obtained.

While I have shown only the preferred embodiments of my invention, it should be understood that various changes, or modification, may be made within the scope of the appended claims without departing from thespirit thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, it will be noted that I have shown a fragmentary portion of a batchor plant D in FIG. 1, and the details of this batchor plant are more fully disclosed in my U.S. Pat.

No. 3,617,031, dated Nov. 2, 1971. As disclosed in this earlier patent, measured amounts of sand, gravel and cement are delivered to a pair of spaced chamber 10 that are arranged at an elevation above a roadway II so that a transit concrete mixer E may be driven into a loading position beneath of chambers, as shown in FIG. 1. Each chamber 10 has gates 12 which may be opened for discharge of the concrete components from the chambers. Moreover, valve-controlled conduits 13 are provided adjacent to the chambers, whereby a measured amount of water may be mixed with the concrete components being discharged from the chambers.

Turning now to the details of the transit concrete mixer E, a vehicle 14 has a rotatable drum l5 rotatably mounted thereon. This vehicle has been shown as a semi-trailer, but a truck could be used. The drum is provided at its front and rear ends with openings 16 and 17, respectively, and front and rear chutes 18 and 19, respectively, register with these openings for delivering the concrete components to the interior of the drum.

It will be observed from FIG. 1 that the front chute 18 is located to register with the gates 12 of one of the chamber 10, while the rear chute 19 registers with the gates 12 of the other chamber 10, whereby charges of the concrete components may be delivered simultaneously into both ends of the drum, as shown in FIGS. 1 and 6, or only the front chute 18 may be used for charging the drum with concrete components, as shown in FIG. 8. The drum 15 is normally disposed horizontally, and thus larger charges of the concrete components may be placed in the drum and the components will not separate from one another as the drum is rotated. In this connection, it is well known that transit mixers wherein the rotating drum is arranged on a slope will cause separation of the concrete components, the cement being the heavier material naturally goes to the bottom, thereby producing non-uniform mixes of the sand, gravel and cement. Also, larger gravel will settle to the bottom in a slope-type drum.

The drum 15 is pivotally supported near its rear end on the vehicle 14 by means of a journal shaft 20, and a hydraulic jack 2], or the like, is provided for raising the front end of the drum, as shown by dot-dash lines in FIG. 1, whereby the mixed concrete components may be discharged from the outlet opening 17 in the rear end of the drum, after these concrete components have been mixed in the manner hereinafter described in detail. A powered belt conveyor 22 is provided to receive the mixed concrete components from the drum.

The front chute 18 is swingably supported on a journal pin 23 from movement into an out-of-the-way position so as to clear the front end cone 24 of the drum prior to elevating the latter. This front chute may be swung on the journal pin 23 by a hydraulic 'jack 25, or the like. The rear chute 19 may be swingably supported on a journal pin 26 so that this chute may swing as the front end of the drum 15 is elevated and the rear end cone 27 moves slightly to the rear.

For the purpose of rotating the drum 15 about its longitudinal axis 28, an engine 29 has been disclosed on the vehicle 14, and this engine is connected through a reduction unit 30 and drive shaft 31 to sprocket 32 on a drive chain 33 that encircles the drum, or the drum may be rotated by other suitable means. Inasmuch as the drum must be turned in either direction, a reverible transmission 34 has been shown, and the direction of turning of the shaft 31 may be controlled by shift lever 35.

In order to close the front and rear openings 16 and 17, respectively, front and rear gates 36 and 37, respectively, have been provided, these gates being identical with one another. As shown in FIG. 1, each of these gates is swingably supported on a journal pin 38 for opening and closing movements. In FIG. 7, a pair of latch rods 39 have been disclosed, the inner ends of these rods being pivotally attached to a collar 40 which is rotatably supported on the adjacent gate 3637. The intermediate parts of these latch rods pass through bearings 41 fixed to the gates, while the outer ends of the rods 39 may engage with lugs 42 fixed to a suitable part of the drum 15. Handles 43 are fastened to the collar 40 so as to rotate the latter in one direction or the other. When this collar is rotated clockwise, as sug gested by arrow 44 is FIG. 7, the gate will be locked in closed position, while a counterclockwise rotation of the collar, as suggested by arrow 45 will unlock the gate for swinging open (see FIG. 1). A suitable latch 46 has been provided for holding each of the gates in open position.

Referring no to FIG. 2, it will be noted that a front set of moldboard blades A are fixed to the interior of the drum '15 near the front end of the latter, and these front blades are curved in cross-section, as shown in FIG. 3, to define concaved scoops 47 on one side thereof. Moreover, a rear set of moldboard blades B are fixed to the interior of the drum and are disposed near the rear end thereof, and these rear blades define concaved scoops 48 on both sides thereof, asvshown in FIG. 5. The front and rear sets of moldboard blades A and B are inclined in opposite directions with respect to one another.

Moreover, mixing blades C are fixed to the interior of the drum 15, these mixing blades being concaved on one side thereof, as shown in FIG. 4, with the concaved sides 49 being disposed to scoop up the concrete components in the lower part of the drum and carry them upwardly for discharging from an upper part of the drum.

It will be seen from FIG. 2 that front, rear and middle groups C, C and C, respectively, are provided by the mixing blades C. The front and rear groups C and C of mixing blades are disposed between the front and rear sets of moldboard blades A and B, respectively. The middle group C of mixing blades are arranged parallel with the axis 28 of the drum 15, while the front and rear groups C and C are inclined in opposite directions relative to one another.

When concrete components F are delivered simultaneously through both ends of the drum by chutes l8 and 19, as in FIG. 6, thus saving time and labor costs, clockwise rotation of the drum as viewed from its front end will cause moldboard blades A and B to move these concrete components toward the center 50 of the drum. At this time the lower part of the drum will be turning in the direction of arrows 51 and 52 (see FIG. 2), causing moldboard blades A and B to move the I concrete components in the direction of arrows 53 and 54, respectively, causing them to crest upwardly at the center 50 of the drum as shown in FIG. 6. Rotation of the drum in the opposite direction will move the lower part of the drum in the direction of arrow 55, causing the concrete components to move in direction of arrow 56 for discharge through rear opening 17.

Referring now to FIG. 8, after closing rear gate 37 and rotating drum l5 counterclockwise as viewed from its front end (normal discharge rotation), the drum may be loaded from its front end by using chute 18. Then the front gate 36 should be closed and direction of rotation changed to clockwise as viewed from the front end of the drum for mixing the concrete components F in the center of the drum as in FIG. 6.

After the concrete components have been throughly mixed, the rear gate 37 should be opened and the drum rotated counterclockwise again to discharge these concrete components through the rear opening 17.

It is pointed out that by closing both gates 36 and 37, the concrete will retain its heat, it being well known that concrete will set as its gets cold. These gates should be closed during mixing of the concrete components, regardless of whether the drum is loaded from one or both ends of the drum, thus retaining the heat. Also, the mixed concrete will retain its workability, producing a better product, which should be delivered to the job site within about 30 minutes before it tends to set up.

It will be apparent that the concrete components F are crested upwardly at the center 50 of the drum during the mixing action, this being really the point of slump test as low slump concrete is stiff and has very little water content with a rich paste. The term slump test is well known in the art and has reference to the use of an official truncated metal casing that is 12 inches high, with an open base 8 1 inches in diameter and an open top 4 inches in diameter. With the base resting on a surface, the casing is filled with concrete through its top, and then the casing is gently withdrawn from around the concrete. The upper part of the concrete should not slump or settle more than about 3 or 4 inches for the proper mix.

Turning now to the modification of rotatable drum 15 disclosed in FIGS. 9 and 10, it has a cylindrical body shell 57 and a plurality of detachable rear truncated end cones 58 and 59 are provided, each having an outer rim 60 dimensioned to be butted against a rear end 61 of the body shell, and means such as bolts 62 are used for detachably securing a selected cone to the body shell. These cones have central openings 17a and 17b through which mixed concrete components may be discharged from the drum, the size of the openings varying from cone to cone, whereby faster or slower discharge of the concrete may be controlled by selecting a cone having the desired size of outlet opening. The drum 15 shown in FIGS. 9 and 10, of course, will be provided with blades A, B and C as previously described, and likewise will have gates 36 and 37 at the front and rear ends thereof.

I claim:

1. In the method of mixing concrete components in a transit mixer, wherein a rotatable drum is provided with a series of inclined blades on its interior, the blades being disposed to move concrete compontnts delivered to the interior of the drum toward the center of the drum when the latter is rotated in one direction and to move them toward an end of the drum when the drum is rotated in the opposite direction, both ends of the drum being provided with openings, the steps of:

a. charging the drum through at least one end opening with the concrete components;

b. rotating the drum in said one direction to move the concrete components toward the center thereof for mixing them, both end openings being closed during the mixing action to retain the heat of the concrete;

(1. and subsequently rotating the drum in said opposite direction for discharging the mixed concrete components through an end opening of the drum.

2. The method of mixing concrete components in a transit mixer, as set forth in claim 1;

d. and in which the concrete components are delivered to the drum through one end thereof, and are discharged through the opposite end thereof.

3. The method of mixing concrete components in a transit mixer, as set forth in claim 1;

d. and in which the concrete components are delivered to the interior of the drum through the front end thereof while the rear end of the drum is closed, elevating the front end of the drum, and discharging the mixed concrete components through the rear end of the drum.

4. The method of mixing concrete components in a transit mixer, as set forth in claim 1;

d. and in which the concrete components are delivered to the interior of the drum simultaneously through both the front and rear ends thereof, and are discharged through the rear end of of the drum.

5. In a transit concrete mixer:

a. a rotatable drum having openings provided in the front and rear ends thereof;

b. driving means operable to selectively rotate the drum in either direction about its longitudinal axis;

c. feed means operable to charge the drum from at least one end thereof through the opening therein with concrete components;

d. a series of inclined moldboard blades fixed to the interior of the drum to move the concrete components toward the center of the drum for mixing them when the drum is rotated in one direction, and to move them through an opening in an end of the drum for discharge when the drum is rotated in the opposite direction;

e. and gates provided for selectively closing the openings in the front and rear ends of the drum.

6. The transit concrete mixer, as set forth in claim 5;

f. and in which the feed means are operable to charge the drum with the concrete components simul taneously through both ends of the drum.

7. The transit concrete mixer, as set forth in claim 5;

. and in which mixing blades are fixed to the interior of the drum, these mixing blades being concaved on one side thereof, with the concaved sides being disposed to scoop up the concrete components in the lower part of the drum and carry them upwardly for discharging from an upper part of the drum.

. The trans it concrete mixer as set forth in claim 5;

and in which theiseries of blades include a front set of moldboard blades disposed near the front end of the drum, and these front blades being curved in cross-section to define concaved scoops on one side thereof;

g. the series of blades further including a rear set of moldboard blades disposed near the rear end of the drum, and these rear blades defining concaved scoops on both sides thereof;

h. and the front and rear sets of moldboard blades being inclined in opposite directions with respect to one another.

9. The transit concrete mixer, as set forth in claim 8;

i. and in which front, rear and middle groups of mixing blades are fixed to the interior of the drum, these mixing blades being concaved on one side thereof, with the concaved sides being disposed to scoop up the concrete components in the lower part of the drum and carry them upwardly for discharging from an upper part of the drum;

j. the front and rear groups of the mixing blades being interposed between the front and rear sets of moldboard blades, respectively, and the middle group of mixing blades being arranged parallel with the axis of the drum; the front and rear groups of mixing blades being inclined in opposite directions relative to one another.

10. In a transit concrete mixer:

a. a rotatable drum having a cylindrical body shell;

b. a plurality of detachable rear truncated cones, each having an outer rim dimensioned to be butted against a rear end of the body shell;

c. each cone having a central outlet opening therein through which mixed concrete components may be discharged from the drum, and the size of the openings varying from cone to cone, whereby faster or slower discharge of the concrete components may be controlled by selecting a cone having a desired size of outlet opening;

d. and means for detachably securing a selected cone to the body shell. 

1. In the method of mixing concrete components in a transit mixer, wherein a rotatable drum is provided with a series of inclined blades on its interior, the blades being disposed to move concrete compontnts delivered to the interior of the drum toward the center of the drum when the latter is rotated in one direction and to move them toward an end of the drum when the drum is rotated in the opposite direction, both ends of the drum being provided with openings, the steps of: a. charging the drum through at least one end opening with the concrete components; b. rotating the drum in said one direction to move the concrete components toward the center thereof for mixing them, both end openings being closed during the mixing action to retain the heat of the concrete; d. and subsequently rotating the drum in said opposite direction for discharging the mixed concrete components through an end opening of the drum.
 1. In the method of mixing concrete components in a transit mixer, wherein a rotatable drum is provided with a series of inclined blades on its interior, the blades being disposed to move concrete compontnts delivered to the interior of the drum toward the center of the drum when the latter is rotated in one direction and to move them toward an end of the drum when the drum is rotated in the opposite direction, both ends of the drum being provided with openings, the steps of: a. charging the drum through at least one end opening with the concrete components; b. rotating the drum in said one direction to move the concrete components toward the center thereof for mixing them, both end openings being closed during the mixing action to retain the heat of the concrete; d. and subsequently rotating the drum in said opposite direction for discharging the mixed concrete components through an end opening of the drum.
 2. The method of mixing concrete components in a transit mixer, as set forth in claim 1; d. and in which the concrete components are delivered to the drum through one end thereof, and are discharged through the opposite end thereof.
 3. The method of mixing concrete components in a transit mixer, as set forth in claim 1; d. and in which the concrete components are delivered to the interior of the drum through the front end thereof while the rear end of the drum is closed, elevating the front end of the drum, and discharging the mixed concrete components through the rear end of the drum.
 4. The method of mixing concrete components in a transit mixer, as set forth in claim 1; d. and in which the concrete components are delivered to the interior of the drum simultaneously through both the front and rear ends thereof, and are discharged through the rear end of of the drum.
 5. In a transit concrete mixer: a. a rotatable drum having openings provided in the front and rear ends thereof; b. driving means operable to selectively rotate the drum in either direction about its lonGitudinal axis; c. feed means operable to charge the drum from at least one end thereof through the opening therein with concrete components; d. a series of inclined moldboard blades fixed to the interior of the drum to move the concrete components toward the center of the drum for mixing them when the drum is rotated in one direction, and to move them through an opening in an end of the drum for discharge when the drum is rotated in the opposite direction; e. and gates provided for selectively closing the openings in the front and rear ends of the drum.
 6. The transit concrete mixer, as set forth in claim 5; f. and in which the feed means are operable to charge the drum with the concrete components simultaneously through both ends of the drum.
 7. The transit concrete mixer, as set forth in claim 5; f. and in which mixing blades are fixed to the interior of the drum, these mixing blades being concaved on one side thereof, with the concaved sides being disposed to scoop up the concrete components in the lower part of the drum and carry them upwardly for discharging from an upper part of the drum.
 8. The transit concrete mixer, as set forth in claim 5; f. and in which the series of blades include a front set of moldboard blades disposed near the front end of the drum, and these front blades being curved in cross-section to define concaved scoops on one side thereof; g. the series of blades further including a rear set of moldboard blades disposed near the rear end of the drum, and these rear blades defining concaved scoops on both sides thereof; h. and the front and rear sets of moldboard blades being inclined in opposite directions with respect to one another.
 9. The transit concrete mixer, as set forth in claim 8; i. and in which front, rear and middle groups of mixing blades are fixed to the interior of the drum, these mixing blades being concaved on one side thereof, with the concaved sides being disposed to scoop up the concrete components in the lower part of the drum and carry them upwardly for discharging from an upper part of the drum; j. the front and rear groups of the mixing blades being interposed between the front and rear sets of moldboard blades, respectively, and the middle group of mixing blades being arranged parallel with the axis of the drum; the front and rear groups of mixing blades being inclined in opposite directions relative to one another. 